Hi Melissa and congrats.
Disney is very expensive but please don't let this deter you from a great honeymoon. As you will have a 5 day pass and the both of you haven't been to Disney in awhile, you will probably be spending more time (6 to10 hours a day) visiting and enjoying the parks. Food wise, I usually tell people that $50 per person per day is easy to use and I have seen many others set this limit as well. I know this seems high but you have to realize that hamburgers, fries and a coke in the MK will cost you $9.00 per person. Bottle of water or soft drink each will cost $2.00 up to $2.50 each. Small box of popcorn or ice cream $2.50 on up. You will save money by eating breakfast in your room and stopping in FL to purchase snacks and soft drinks as well. But honestly, you probably will buy at least one snack and some type of meal in the parks per day. Check out a site called wdwig.com. This site has menus for all the parks sitdown and counter service restaurants which is a great guide to show you some basic cost.
Next, souvenirs is a hard one to predict. You may think that your not going to buy a lot but may go down and want some fun reminders of your trip. For instance, you may want to purchase a ride photo of the both of you screaming your lungs out as you drop down the waterfall in Splash Mountain. Well there goes $15 dollars. They do have shirts in all sizes, there goes another $20-$50. My personal favorites are the antenna toppers which last visit went up from $3 to $4. You may forget your hat and absolutely need to purchase the goofy hat with ears for $30. Trust me, you never really know what you may spend on souvenirs at Disney. Hint, go to a few souvenir shops in Kissimmee (Hwy 192) as you can save some money purchasing a few things there.
Lastly, It is certainly a good thing to set a budget and $1,000 is doable but do a little more studying before you go. It never hurts to have an extra $200 or $300 on you just in case and don't forget, it may be awhile before you get to go again, and in the end it is your honeymoon. Find time to do something special for each of you including one really nice meal out.
P.S. Not everything at Disney has a pricetag on it. For instance, you can find romance sitting on the beach at the Poly (you do not need to be staying there) waiting for Wishes (fireworks show at MK) to go off. If you stay there long enough you will also see the water pagent go by shortly after 9:00 p.m. Best of luck to you.